Request for Comments (RFC) 5578, an Internet Engineering Task Force (IETF) standard, defines the Point-to-Point Protocol over Ethernet (PPPoE) with Credit-Based Extensions for Ethernet-based communications between a router and a modem that operates in a variable bandwidth environment and has limited buffering capabilities. To support the credit-based flow control extensions, PPPoE peers can grant each other forwarding credits. The grantee is allowed to forward traffic to the peer only when it has a sufficient number of credits. When credit-based forwarding is used on both sides of the session, the radio client can throttle traffic by limiting the number of credits it grants to the router. RFC 5578 is a promising technology which can serve as a bridge to merge two very different worlds, IP routing and mobile radio, while taking advantage of the strengths of each.
Attempts on using the RFC 5578 with a PPPoE agent embedded into a Layer 2 switch have not been successful. To address this compatibility issue, modifications to the RFC 5578 implementation have been proposed such that the destination MAC (Media Access Control) address of the protocol negotiation message is replaced by the pre-defined MAC address once it is received by the Layer 2 switch. However, this will cause incompatibilities with other RFC 5578 compliant COTS devices. In addition, users may not be able to remotely access the switch because the access requests will be forwarded to the device with the pre-defined MAC address. Furthermore, when the network condition changes, e.g., the destined device is replaced, it requires the system administrators to manually reconfigure the switch at runtime. The reconfiguration process is time-consuming and error-prone which is undesirable.